You're supposed to be able to run the ROM->CAP converter tool to convert your BIOS to a .CAP system format, then you flash the .CAP new BIOS.
1. Download converter tool from ASUS website.
2. Rename converter as "SABERX79.ROM" and put on USB stick.
3. Plug in to white USB port next to BIOS button on Mobo panel
4. With power on on the Power Supply but not on the computer (just idle power, whatever you call it), hold BIOS button until it starts flashing.
5. Let it run (takes a few minutes) until the light stops flashing.
6. Then put your new BIOS on the flash drive and rename it "SABERX79.CAP"
7. Then repeat the process.
If the light blinks for a second or two then turns solid blue, it aint working. I'm having trouble getting mine to work too (see my thread http://www.tomshardware.com/answers/id-2124469/sabertooth-x79-strange-problems.html).
Let me know if you get yours to work. Maybe we can help eachother out!